Rail mounted drilling machine for furnace tap hole



June 23, 1970 TOSHIKAZU HONDA ET AL 3,516,651

RAIL MOUNTED DRILLING MACHINE FOR FURNACE TAP HOLE Filed Oct. 16, 1967 5 Sheets-Sheet 1 T HKAZU ND T AAKI MINATO 7 I flaw/29%; M: mm

ATTO RN E YS Jun 23, 1970 TOSHIKAZU HONDA ET AL 3,516,651

RAIL MOUNTED DRILLING MACHINE FOR FURNACE TAP HOLE Filed Oct. 16, 1967 5 Sheets-Sheet 2 lll 48 8O 17 I 8r 25 2 1 a1 T [3 e w II r15: J 519i: 2 l 7-,. i3

June 23, 1970 TOSHIKAZU HONDA ET 3,516,651

. RAIL MOUNTED DRILLING MACHINE FOR FURNACE TAP HOLE Filed Oct; 16, 1967 K I 5 Sheets-Sheet :5

/,\'\1;\r01 s TOSHIKAZU HONDA 6O TADAAKI MINATO By ZZ f 63 s fw' ATTORN E YS June 23, 1970 TOSHIKAZU HONDA ET AL 3,516,651

RAIL MOUNTED DRILLING MACHINE FOR FURNACE TAP HOLE Fild Oct. 16, 1967 5 Sheets-Sheet 4.

7 ATTORNEYS 5 Sheets-Sheet 5 TOSHIKAZU HONDA- ET AL RAIL MOUNTED DRILLING MACHINE FOR FURNACE TAP HOLE Filed Oct. 16, 1967 FIG.9

June 23, 1970 United States Patent 3,516,651 RAIL MOUNTED DRILLING MACHINE FOR FURNACE TAP HOLE Toshikazu Honda, Kure-shi, and Tadaaki Minato, Hiroshima-shi, Japan, assignors to Toyo Kogyo Company Limited, Hiroshima-ken, Japan Filed Oct. 16, 1967, Ser. No. 675,493 Int. Cl. C2111 7/12 US. Cl. 26642 14 Claims ABSTRACT OF THE DISCLOSURE A blast furnace tap hole drilling machine having a carriage movably mounted on rails positioned near the bustle pipe of the furnace. A hanger is pivotally mounted on the carriage, and a guide channel is pivotally mounted on the hanger. A rock drill and a reverse impact device are slidably mounted on the guide channel. Power means are provided to cause the guide channel and the hanger to fold up toward the carriage, to retract the drill machine away from the furnace, and to operate the rock drill.

This invention relates to a drilling machine for drilling tap holes in blast furnaces and more particularly to a drilling machine by which the drilling operations are carried out precisely and easily, and the succeeding furnace activities are not interrupted, the drilling machine being folded and retracted from the furnace after the drilling operation.

Heretofore, when drilling a tap hole the drilling machine has been laid on a mounting base in front of the blast furnace.

In front of the tap hole of the blast furnace, however, the crane for carrying heavy materials, the mud gun for closing the tap hole, and other structures are often laid. Therefore, setting the said mounting base for the drilling machine on the floor in front of the furnace makes the space in front of the furnace narrower, causes the removal of molten iron to be more difficult, and consequently decreases work efficiency as a whole.

It is generally desired that the drilling machine be able to drill the tap hole exactly and surely, that after the drilling the machine be moved away from the tap hole to avoid the violent heat effect of the molten iron, that the machine be adjusted to a predetermined location even if a gap exists between the furnace and the drilling machine due either to difficulty in achieving exact initial relative positioning or to heat deformation of the furnace body itself by putting fire to the furnace, and that after the drilling of the hole, the drill steel be withdrawn before the front end of the said drill steel is damaged by the molten iron. No drilling machines yet developed have completely satisfied these demands.

The first object of this invention is to make the operations of removing the molten iron and the accompanying operations safe and effective by setting the drilling machine in front of the blast furnace without the use of a mounting base.

The second object of this invention is to hold a rock drill surely to the furnace body so that the drill steel can precisely drill a straight hole in the furnace body.

The third object of this invention is to maintain a relative spacing between the furnace body and the rock drill by adjusting a position setting even if the relative spacing changes due either to difliculty in achieving exact initial positioning or to heat deformation of the furnace body.

The fourth object of this invention is to retract the Patented June 23, 1970 drilling machine far from the furnace body in a compactly and surely folded state immediately after the removal of the molten iron.

The fifth object of this invention is to withdraw the drill steel as rapidly as possible by imparting reverse impact force on the said drill steel after the drilling of the tap hole is complete.

The invention will be further described with reference to the accompanying drawings which are given by way of example, and in which:

FIG. 1 is a partial sectional side view of the drilling machine according to this invention positioned on the furnace body;

FIG. 2 is a plan of the drilling machine according to this invention positioned on the furnace body;

FIGS. 3 and 4 are a cross sectional side view and a cross sectional front view, respectively, of a rolling device according to this invention showing a carriage of the drilling machine on rails;

FIG. 5 is a sectional front view taken along the line VV in FIG. 1;

FIG. 6 is a back view partially in section taken along the line VI-VI in FIG. 1;

FIG. 7 is a partial sectional view taken along the line VIIVII in FIG. 6;

FIG. 8 is a sectional front view taken along the line VIII-VIII in FIG. 1;

FIG. 9 and FIG. 10 are sectional front views taken along the lines IX-IX and X-X, respectively, in FIG. 1; and

FIG. 11 is a sectional view of a reverse impact device fitted on a well-known drill.

Referring to the drawings, the upper part around the outside of a body 12 of a blast furnace is positioned a bustle pipe 13 wherein is circulated the hot blast supplied from a suitable hot blast stove (not shown in drawings) and delivered through a duct 14 into the furnace. A beam 15 secured at the side of the furnace body 12 is equipped with two horizontal rails 16 at a certain interval. On the said rails 16 a carriage 18 is slidably mounted by means of rolling devices 17, hereinafter described in detail. A pair of brackets 19, which are slidably mounted on both sides of the carriage 18, are equipped with a hanger 20 the upper end of which is connected to brackets 19 by means of shafts 21. Thereby on operating a first chain-feed motor 22, the hanger 20 is swung toward the carriage 18 around shafts 21 by means of chain 23. A guide channel 25, which is rotatably connected to the lower end of the hanger 20 by means of a shaft 24, is reciprocally fitted with a well-known rock drill 26; or, if necessary, a rock drill 26 with a reverse impact device 27 positioned on the same axis. Upon the operation of an air hoist 28, the said guide channel 25 is swung around shaft 24 to a certain angle with the frame 20 by means of the wire 29. Thus, when the hanger 20 and guide channel 25 are extended to given angles with carriage 18 and hanger 20, respectively, a hook 30 secured to the front end of the guide channel 25 fits over latch 31 which is fixed to the furnace body 12.

More detailed description of the installation are as follows. As shown in FIG. 3 and FIG. 4, the rolling device 17 consists of a pair of bearing plates 34 fastened to the upper surface of an I-beam 18' and a plate 32 fixed between two I-beams 18' of both sides of carriage 18 at a certain interval by bolts 33. Rollers 35 which are rotatably supported on bearings 36, each end of which is fixed on said bearing plates 34, are mounted on rails 16. Another pair of bearing plates 37 is fastened to plate 32 and interposed between bearing plates 34 by bolts 38.

A roller 39 is rotatably mounted by means of a bearing 40 secured to the bearing plates 37 and located with its upper margin adjacent the lower surface of rail 16 to thereby prevent function of the position of carriage 18. In FIG. 1 and FIG. 2, reference numerals 41, 42 and 43 indicate cross members which are fixed between the rails 16 at a proper interval. One end of a chain is wound around a second chain-feed motor 44 mounted on the upper surface of the cross member 41 and is connected with a lug 49 on a plate 48 fixed on the carriage 18. The other end of the chain 45 is connected with a lug 53 fixed on the plate 48 through a sprocket wheel 47 which is rotatably set on brackets 46 on beam 15 and through sprocket-wheels 51 which are rotatably set by brackets on the lower surface of the cross members 42 and a sprocket-wheel 52 which is rotatably set on the upper surface of the cross member 43. By operating the chainfeed motor 44, the carriage 18 is moved along the rails 16.

As shown in FIG. 5, on the upper end of the I-beam 18' at both sides of the carriage 1-8 are slidably mounted a pair of guide plates 54 and 55, the ends of which are fastened by bolts 56 so as to make said plates selectively loose or tight. Flanges of the guide plate 55 are fastened to the upper part of the brackets 19 and by the adjustment of bolts 56, the hanger 20 is either fixed or travels along I-beam 18' of the carriage 18. As shown in FIGS. 6 and 7, the hanger 20 consists of a first frame 58 and a second frame 59. The first frame 58 consists of two channels connected by cross members 60. The second frame 59 consists of two channels connected by cross members 61 and 61' so that the rear surfaces of the channels of frame 58 contact the rear surfaces of the channels of frame 59. Guide plates 62 and 63 are fixed on the ends 59' of the channels of frame 59 and slide longitudinally along channels of frame 58. The reference numeral 64 indicates a supplementary member for strengthening connection of the guide plate 62 and the cross member 61. A fixing plate 65 established inside the channel of the frame 59 is firmly fitted with one end of a bolt 66, the other end of which passes through a hole of a bracket 67 fixed on the channel of the first frame 58. By adjusting nuts 68, the second frame 59 is either fixed to or slidable along the frame 58, whereby the length of the hanger 20' may be regulated. Both end parts 69' of the plate 69 fixed on the midpart of the frame 58 are slidably inserted into a mounting 71 which is fastened by bolts 70. A beam 72 fixed to the mounting 71 is firmly secured to the end of a supporting arm 73, the other end of which is inserted in a guide hole 76 of an upper connecting rod 75, the end of which is supported with a bracket 74 established on the I-beam 18' of the carriage 18. One end of a bolt 77, the other end of which is fixed to the beam 72, passes through a bracket 78 fixed on the lower part of the frame 58, and by adjusting the nuts 79, the mounting 71 is either fixed to or slides along the plate 69 of frame 58, whereby the angle of the hanger to the carriage 18 may be regulated. One end of the chain 23 wound around the first chain-feed motor 22 is connected with a lug 82 on the cross member 60 of the first frame 58 through a sprocket-wheel 81 supported by two supporting members fixed on the middle of the rear part of the carriage 18, and the other end of the chain 23 is connected with a lug 87 on the back surface of the cross member 60 through a sprocket-wheel 84 supported by means of bracket 83 on the middle of the front part of the carriage 18, and a sprocket-wheel 86 supported by means of bracket on the front and lower part of the carriage 18. In FIG. 1 and FIG. 9, to both ends of a fixed plate 88 on the upper surface of the guide channel 25 are slidably inserted a mounting fastened by bolts 89. By adjusting bolts 89 the mounting 90 is either fixed on the fixed plate 88 or slides longitudinally along the guide channel 25. To the said mounting 90 is firmly fitted a pair of elevating members 93 on the outside of which are secured hanger receivers 92 having slopes 91 moderately slanted toward the guide channel 25. In the upper parts of the elevating members 93 are holes 94, the axes of which are spaced from and parallel to guide channel 25. Both ends of a supporting rod 95 fitted with the lower parts of the elevating members 93 supported by inserting them into holes 98 of lower connecting rods 97 the upper ends of which are rotatably connected with a lug 96 fixed to the lower surface of the cross member 61 of the second frame 59. The end of the wire 29 of the air hoist 28 mounted on the carriage 18 is connected with a lug 102 fixed on the front part of the guide channel 25 through two pulleys 100 and 101 which are located at the front part and the midpart of the carriage, respectively.

A pair of hanging devices 103 installed at the rear and lower parts of the carriage 18 make the elevating members 93 hang on the carriage 18 when the hanger receivers 92 contact the lower surface of the hanger 20 after the elevating members 93 have passed through a space 60 by the operation of first chain-feed motor 22 and air hoist 28, whereby the guide channel 25 travels from the full line position to the dashed line position shown in FIG. 1. With reference to FIG. 10, a fiuid cylinder 1% is hung by means of brackets 105 on a cross member 104 which is positioned between both I-beams 18' of the carriage 18. The end of a piston rod 107 passes through a hole in bracket 108 on the said cross member 104. By operating the fluid cylinder 106, the elevating members 93 are supported by inserting the end of the piston rod 108 into the hole 94. As shown in FIG. 6 and FIG. 8, at the lower ends of connecting pieces 109 whose upper ends are firmly secured to the cross member 61' of the hanger 20, is bridged a supporting shaft 24, on which are rotatably suspended a pair of hanging arms 111 fitted with a plate 110, and into a guide space 114 between the said plate and a plate 113 fastened thereto by bolts 112 are inserted a pair of interposing pieces 115 which are fixed to the upper surface of the guide channel 25. By adjusting the said bolts 112, the guide channel 25 is either fixed or slides back and forth relative to both plates 110 and 113. Rollers which are rotatably supported by means of the bearings 118 on the supporting members 117 fitted at the lower part with a plate 116 are mounted on rails 25' of the guide channel 25, and the lower surface of the plate 116 is fitted by means of bolts 122 with a plate 121 for hanging the base 27 of a reverse impact device 27. Because the means for mounting a rock drill 26 on the rails 25' are similar to the means for mounting the reverse impact device 27, the drawings and the detailed description of the drill mounting means are omitted.

Both supporting members 117 for the reverse impact device 27 and the drill 26 are so constructed that they may be connected in union or separately by attaching to connecting rods 123, 124 which are fixed on the sides of the said supporting members 117 by means of connectors 125. The ends of a chain 127 fed by a third chain-feed motor 126 which is mounted on the guide channel 25 are connected with the plates 116 of the reverse impact device 27 and the rock drill 26 respectively, through sprocket-wheels 128, 129 supported rotatably on the front and rear ends of the guide channel 25. By operating the third chain-feed motor 126 the reverse impact device 27 and the rock drill 26 slide back and forth along the guide channel 25. The reason for making the reverse impact device 27 and the drill 26 removable by means of the connectors 125, is that, in this invention, the use of the reverse impact device 27 is not always necessary, since often only the rock drill 26 is used on the guide channel 25. In the latter case, a shank rod which passes through the reverse impact device 27 and the rock drill 26, of which description will be given later, is generally exchanged for a common drill steel and the end of the chain 127 must be connected with the plate 116 for the rock drill 26.

The description of the reverse impact device 27 will be made with reference to FIG. 11. An annular piston 131 is closely fitted inwardly of a cylinder 130 and bushings 133, 134 inserted in a head 132 set on the rear end of the cylinder 130. A shank rod 136 having a blow-hole 135 passes through the center of cylinder 130 and is longitudinally slidably supported by bearing 140 of a head 139 and an inner bore of piston 131. The rear end of piston 131 is constructed so as to strike a collar 137 of shank rod 136 which is slidably supported by bearing 138 at head 132. The rearward movement of piston 131 thereby being limited. A valve device 144 furnished within the front interior of cylinder 130 is so constructed that the inside of a guide plate 146 having annular openings 145 which communicate with air inlet opening 141 is set on the shank rod 136. A valve chest 148 is set, by means of a fixing pin 149, outside of the guide plate 146, thereby keeping clearance as an air passage 147. One end of a passage 150 provided in the valve chest 148 is communicated with the annular opening 145, while the other end is communicated with a valve chamber 151. On the rear outside of guide plate 146 is slidably set a valve 152, L-shaped in section. The front or rear surfaces of the valve 152 maintain contact with the rear surface of the valve chest 148 or with a valve seat 153 respectively, by means of pressure within cylinder 130 whereby the compressed air from air inlet opening 141 is supplied either to the front chamber 142 through the annular openings 145, air passage 150 and the valve chamber 151, or to the rear chamber 143 through the annular openings 145, air passage 150, valve chamber 151, the passage 147, and an air passage in the cylinder wall which is not shown in the drawings. Splines 154, cut on the rear part of the shank rod 136, are slidably fit into splined grooves 157 of a rotation sleeve 156 set in the front head 155 of the rock drill 26, and the rear end of shank rod 136 is struck by a piston 158. According to this invention, when the reverse impact device 27 is used together with the rock drill 26, the means for feeding compressed air from the air source must be controlled by a well-known three-way cock, so that the air will not be fed to the rock drill 26 during the time it is fed to the reverse impact device 27, or so that the air will not be fed to the reverse impact device 27 during the time it is fed to the rock drill 26. Further description of the air controlling circuit is omitted, since anyone skilled in the art would easily understand it.

The front end of the shank rod 136 is connected, by means of connector 161, with the rear end of drill steel 160 supported by a centralizer 159 on the front end of the guide channel 25.

Reference numeral 162 indicates the tap hole to be drilled at a given angle in the furnace body 12, and in which mud is charged. Reference numeral 163 indicates a wiper, one end of which is rotatably mounted on the side of the bearing plates 34, and the other end of which moves in contact with the rails 16 for cleaning.

The operation of the drilling machine constructed as above is as follows. By operating the second chain-feed motof 44, the rollers 35 are rolled on the rails 16 by means of the chain 45. When the mid-part of the carriage 18 coincides with a perpendicular plane including the axis of the tap hole 162 of the furnace body 12, chain-feed motor 44 is stopped and the carriage 18 is fixed on the rails 16. After detaching the piston rods 107 from the guide holes 94 of the elevating members 93 by operating the fiuid cylinder 106, the air hoist 28 is operated, whereby the guide channel 25 is rotated on the shaft 24 by means of wire 29 until the ends of lower connecting rod 95 arrive at the lowest part of the guide holes 98 of the lower connecting rods 97, and then the air hoist is stopped. Simultaneously with the above operation, the first chain-feed motor 22 is operated, whereby the hanger 20 is rotated on shafts 21 by means of chain 23 until the hanging arms 73 arrive at the lowest part of the guide holes 76 of the upper connecting rods 75, and then motor 22 is stopped. Downward movementof the hanger 20 and the guide channel 25, however, can be carried out by their dead-Weights without operating the first chain feed motor 22 and the air hoist 28.

The hook 30 of the guide channel 25 is then put on latch 31 of the furnace body, and the center line of the drill steel 160 necessarily coincides with the tap hole 162 of the furnace body 12. Otherwise, the operator must perform the following adjustments as necessary.

(a) By loosening the bolts 56, fastening the upper part of the I-beams 18' of the carriage 18, the hanger 20 and the guide channel 25 are moved back or forth the desired distance, whereby the distance between the front end of guide channel 25 and furnace body 12 is adjusted. Bolts 56 are then tightly fastened.

(b) By loosening the nuts 79 provided at the lower part of the first frame 58, the mountings 71 may be moved up or down on the plates 69, whereby the location of the hanging arms 73 at the lower part of the guide holes 76 of the upper connecting rods 75, that is, the set angle of the hanger 20 to the carriage 18, is adjusted. Nuts 79 are then tightly fastened.

(c) By loosening the nuts 68 provided on the first frame 58, the second frame 59 may be moved up or down onto the first frame 58 by the desired amount, whereby the length of the hanger and the set angle of the guide channel 25 to the hanger 20 is adjusted. Bolts 68 are then tightly fastened.

(d) By loosening the bolts 112 on the plates shown in FIG. 8 and the bolts 89 on the mounting 90 shown in FIG. 9, the guide channel 25 may be moved back or forth toward the hanger 20 by the desired amount, whereby the distance between the front end of guide channel 25 and the furnace body 12 is adjusted. Bolts 89 are then tightly fastened.

(e) By any suitable combination of the above operations (a) to (d), the final adjustment is made.

On putting the hook 30 on the latch 31 so that the center line of drill steel coincides with the tap hole 162, the drilling operation is made ready.

By operating the third chain-feed motor 126, together with the rock drill '26- to impart rotation and impacting motions to drill steel 160, the rock drill 26 is moved along guide channel 25 through the rollers by means of chain 127, whereby the tap hole 162 of the furnace body 12 is drilled half way by the point of the drill steel 160. As soon as the drilling is over, the action of the rock drill 26 is stopped and the third chainfeed motor 126 is reversed, whereby the rock drill 26 goes back along the guide channel 25, and the drill steel is withdrawn from the tap hole 162.

Then, the drill steel 160 is then exchanged for a consumable tapping rod, and the rock drill 26 is moved along the guide channel 25 by operating the third chain-feed motor 126, whereby the said consumable tapping rod, to which rotating and impacting action is given, pierces the furnace wall to form the rest of the tap hole. During the above operation, it oftens happens that the consumable tapping rod cannot easily be withdrawn because the point of the rod is often welded by the molten iron in the tap hole. In such a case if the reverse impact device 27 is operated together with the rock drill 26, the withdrawal of the consumable tapping rod is made easier.

The operation of the reverse impact device 27, with reference being made to FIG. 11, is as follows. The compressed air delivered to the air inlet opening 141 flows into the rear chamber 143 through the annular opening 145, the passage 150, the valve space 151, the passage 147 and the passage in cylinder wall 130, and causes piston 131 to move to the left in FIG. 11. Thereafter, the rear chamber 143 is connected with a vent opening and the pressure is reduced, but the piston 131 continues to the left by its inertial force and elevates the pressure in the front chamber 142, whereby the valve 152 is moved forward to change the air flow. The piston 131 then moves to the rig-ht by the flowing of the air fed to the 7 valve space 151 into the front chamber 142. The front chamber 142 is soon communicated with the vent opening, but the piston 131 continues moving toward the right by its inertial force, whereby the rear end of the piston 1 41 strikes the collar 137 of the shank rod 136 and forcedly moves the shank rod backward.

Because the pressure in the cylinder rear space 143, is then elevated, the valve 152 is moved backward and the air is fed to the passage 147. Thus, by the reverse impact force given to the shank rod 136 by means of the repeating action of the piston 131 and by the inverse rotation of the feed motor 126, the drill 26 and the reverse impact device 27 can be moved backward along the guide channel 25.

After the tap hole of the blast furnace is opened, the rotation of air hoist 28 is reversed, and the guide channel 25 is rotated upwardly on the shaft 24 by means of wire 29. The supporting rods 95 slide upwardly within the guide holes 98 of the lower connecting rods 97. The air hoist 28 is then stopped.

Then, by rotating the first chain-feed motor 22 in reverse the hanger 20 is rotated on the shafts 21 upwardly by means of chain 23. The supporting arms 73 slide upwardly within the guide holes 76 of the upper connecting rods 75. The chain-feed motor '22 is then stopped. Thereby the hanger 20 and the guide channel 25 are folded to the position shown in the dashed lines from the position shown in the solid lines in FIG. 1. At this time, the centers of holes 94- of the elevating members 93 coincide with the pistons 107 in the fluid cylinder 106. The pistons 107 are projected sideways through the holes 94 by operating the fluid cylinders 106, while the hanger receiver 90 supports the lower surface of the hanger 20, whereby the guide channel 25 and the hanger 20 can be firmly fixed to the carriage 18. Finally, after the carriage 18 is retracted by means of chain 45 far from the furnace body 12 along the rails 16 by operating the second chain-feed motor 44, the second chainfeeding motor 44 is stopped and the drilling work of the tap hole is finished.

As seen in the above descriptions, according to this invention, a tap hole of a blast furnace can be drilled precisely and rapidly, and upon the completion of the re moval of the drill, the drill frame can be retracted far from the furnace body. Thereby the removal of molten iron is not interrupted and the drilling machine is not damaged by the high temperature of the molten iron, and consequently the drilling operation can be carried out safely and effectively.

For purpose of exemplification, a particular embodiment of the invention has been shown and described according to the best present understanding thereof. However, it will be apparent that changes and modifications in the arrangement and construction of the parts thereof may be resorted to without departing from the true spirit and scope of the invention.

We claim:

1. A drilling machine for drilling a tap hole in a blast furnace comprising a pair of rails arranged in front of said blast furnace, a carriage mounted to move on said rails, a first chain-feed motor means for moving said carriage, a hanger having lower ends and upper ends, said upper ends rotatably fitted to said carriage, a second chain-feed motor means for rotating said hanger toward said carriage, a guide channel rotatably fitted to the said lower ends of said hanger, air hoist means for rotating said guide channel toward said hanger, a rock drill having a drill steel movably mounted on said guide channel, a third chain-feed motor means for moving said rock drill along said guide channel, and hook means on said guide channel for engaging a latch fixed on said furnace body when the center line of said drill steel coincides with that of said tap hole in said furnace body.

2. A drilling machine for drilling a tap hole in a blast furnace according to claim 1, wherein said upper ends of 8 said hanger are rotatably fitted to shafts having brackets thereon which are slidably mounted on said carriage.

3. A drilling machine for drilling a tap hole in a blast furnace according to claim 1, further comprising arms slidably positioned along said hanger, and upper connecting rods having guide holes therein, said arms being inserted into said guide holes and the ends of said upper connecting rods being rotatably fitted to the rear part of said carriage.

4-. A drilling machine for drilling a tap hole in a blast furnace according to claim 1, further comprising a supporting rod mounted on said guide channel, and lower connecting rods having guide holes therein, said supporting rod being inserted into said guide holes and the ends of said lower connecting rods being rotatably fitted with the rear surface of said hanger.

5. A drilling machine for drilling a tap hole in a blast furnace according to claim 1, wherein said hanger consists of a first frame and a second frame, said second frame being slidably inserted into said first frame, whereby the length of said hanger is adjustable.

6. A drilling machine for drilling a tap hole in a blast furnace according to claim 1, further comprising a pair of plates slidingly secured to said guide channel, said plates having hanging arms thereon rotatably fitted through a shaft to the lower ends of said hanger, and a mounting having elevating members thereon slidingly secured to said guide channel.

7. A drilling machine for drilling a tap hole in a blast furnace according to claim 1, further comprising elevating members having holes therein mounted on said guide channel, and fluid cylinders having pistons therein mounted on the underside of said carriage, whereby when said second chain-feed motor is operated to rotate said hanger toward said carriage, and when said air hoist means is operated to rotate said guide channel toward said hanger, said pistons are inserted into said holes in said elevating members to hold said hanger and said guide channel in a folded position.

8. A drilling machine for drilling tap hole in a blast furnace according to claim 1, further comprising a reverse impact means having a shank rod therein and being mounted on said guide channel.

9. A drilling machine for drilling a tap hole in a blast furnace according to claim 8,;whe1ein said upper ends of said hanger are rotatably fitted to shafts having brackets thereon which are slidably mounted on said carriage.

10. A drilling machine for drilling a tap hole in a blast furnace according to claim 8, further comprising arms slidably positioned along said hanger, and upper connecting rods having guide holes therein, said arms being inserted into said guide holes and the ends of said upper connecting rods being rotatably fitted to the rear part of said carriage.

11. A drilling machine for drilling a tap hole in a blast furnace according to claim 8, further comprising a supporting rod mounted on said guide channel, and lower connecting rods having guide holes therein, said supporting rod being inserted into said guide holes and the ends of said lower connecting rods being rotatably fitted with the rear surface of said hanger.

12. A drilling machine for drilling a tap hole in a blast furnace according to claim 8, wherein said hanger consists of a first frame and a second frame, said second frame being slidably inserted into said first frame, whereby the length of said hanger is adjustable.

13. A drilling machine for drilling a tap hole in a blast furnace according to claim 8, further comprising a pair of plates slidingly secured to said guide channel, said plates having hanging arms thereon rotatably fitted through a shaft to the lower ends of said hanger, and a mounting having elevating members thereon slidingly secured to said guide channel.

14. A drilling machine for drilling a tap hole in a blast furnace according to claim 8, further comprising elevating members having holes therein mounted on said guide channel, and fluid cylinders having pistons therein mounted on the underside of said carriage, whereby when said second chain-feed motor is operated to rotate said hanger toward said carriage and When said air hoist means is operated to rotate said guide channel toward said hanger, said pistons are inserted into said holes in said elevating members to hold said hanger and said guide channel in a folded position.

References Cited UNITED STATES PATENTS ROBERT D. BALDWIN, Primary Examiner 

